Add map transition for observed objects

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 13768 matching lines @@
     if (proto->IsNull()) return isolate->heap()->false_value();
     ASSERT(proto->IsJSGlobalObject());
     obj = JSReceiver::cast(proto);
   }
   return isolate->heap()->ToBoolean(obj->map()->is_observed());
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetIsObserved) {
   SealHandleScope shs(isolate);
-  ASSERT(args.length() == 2);
+  ASSERT(args.length() == 1);
   CONVERT_ARG_CHECKED(JSReceiver, obj, 0);
-  CONVERT_BOOLEAN_ARG_CHECKED(is_observed, 1);
   if (obj->IsJSGlobalProxy()) {
     Object* proto = obj->GetPrototype();
     if (proto->IsNull()) return isolate->heap()->undefined_value();
     ASSERT(proto->IsJSGlobalObject());
     obj = JSReceiver::cast(proto);
   }
   ASSERT(!(obj->map()->is_observed() && obj->IsJSObject() &&
            JSObject::cast(obj)->HasFastElements()));
-  if (obj->map()->is_observed() != is_observed) {
-    if (is_observed && obj->IsJSObject() &&
-        !JSObject::cast(obj)->HasExternalArrayElements()) {
-      // Go to dictionary mode, so that we don't skip map checks.
-      MaybeObject* maybe = JSObject::cast(obj)->NormalizeElements();
-      if (maybe->IsFailure()) return maybe;
-      ASSERT(!JSObject::cast(obj)->HasFastElements());
-    }
-    MaybeObject* maybe = obj->map()->Copy();
-    Map* map;
-    if (!maybe->To(&map)) return maybe;
-    map->set_is_observed(is_observed);
-    obj->set_map(map);
-  }
-  return isolate->heap()->undefined_value();
+  ASSERT(obj->IsJSObject());
+  return JSObject::cast(obj)->SetObserved(isolate);
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_SetObserverDeliveryPending) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);
   isolate->set_observer_delivery_pending(true);
   return isolate->heap()->undefined_value();
 }
 
@@ skipping 213 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal